Reported bugs fixed and changed dependencies so that we could compile

[Lala341]

We change the versions to the libraries to be able to run the application (rxdart, scoped_model). In addition, we solved issue #31 of memory leak, for this the HistoryLimit class was added, which is responsible for verifying the limit to the number of layers within the Navigator stack, the navigator class was also changed, with a new method to add media detail that removes views from the stack if they are very old. We also solved issue #32 , in this when the size of the favorites is very large, the application closes. For this, a new class was added within utils called app_model_db, it stores the favorites in a local database with sqlite, it has the same methods as the previous class and it works with Model, for this the imports to app_model were also modified. We also resolved isuue #33 an overflow in the media detail view, it was modified by changing the widget to a Wrap which makes it easier if the categories exceed the screen size, a new row is generated. We also solved isuue #34 , a method was added within utils to check the status of the internet connection and actor detail was modified to send a message when there is no connection.